Class

silicate mineral

Compound type

nesosilicate

Comments

Forsterite: name by extension of (Fe,Mg)2SiO4 in the range Fe=0-10% - Equivalent Space Group: Pbnm (62)

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Mg$	Magnesium	element	2		constituent element	main
	$Si$	Silicon	element	1		constituent element	main
	$O$	Oxygen	element	4		constituent element	main

Composition comments

Common substitution: Fe

Chemical functions

	Function	Number
	$(SiO_4)^{4-}$	1

Chemical bonds

	Bond	Number
	$\geq Si-O^-$	4

Oxides

Formula	$MgO$	$SiO_{2}$
Mass fraction (%)	57.29	42.71

Strunz

Class

silicates (09)

Division

nesosilicate (09.A)

Family

without additional anions; cations in octahedral [6] coordination (09.AC)

Code

09.AC.05

Dana

Major class

silicates (VIII)

Class

nesosilicate insular SiO4 groups only (51)

Type

with all cations in octahedral [6] coordination (51.03)

Group

Olivine group (51.03.01)

Code

51.03.01.02

Phase type

crystalline

Crystal system

orthorhombic

Crystal class

dipyramidal

Crystal class symbol

mmm (D2h)

Crystal spacegroup

Pnma

Composition order

ordered

Texture

polycrystalline

Molar mass

140.69 $g/mol$

Density

3.271 $g/cm^3$

Refringence type

biaxial

Refringence sign

negative

Birefringence

0.0330

Refraction index $n_{\alpha}$

1.636

Refraction index $n_{\beta}$

1.650

Refraction index $n_{\gamma}$

1.669

Dispersion V

r > v or r < v

Color

green, yellow, yellow green, white

Diaphaneity

transparent to translucent

Luster

vitreous